A complete, infectious virus particle outside a host cell is called a ____.
Correct answer A. virion
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MDCAT Biology MCQs
Page 28 of MDCAT Biology multiple-choice questions with answers. Tap an option to check yourself.
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- Biological Molecules 74
- Coordination and Control 72
- Biology Diagnostic 70
- Cell Structure and Function 67
- Biotechnology 65
- Reproduction 58
- Bioenergetics 55
- Circulation 50
- Inheritance 48
- Digestion 45
- Immunity 45
- Support and Movement 45
- Acellular Life (Viruses) 45
- Homeostasis 45
- Respiration and Gaseous Exchange 45
- Evolution 45
- Enzymes 45
- Cell Cycle 41
- Chromosome and DNA 40
- Biology Introduction 38
- Ecosystem 27
Which is the correct order of events in the lytic cycle of a bacteriophage?
Correct answer C. Attachment, penetration, synthesis, assembly, lysis
During infection of E. coli by phage T4, what actually enters the bacterial cell?
Correct answer C. Only the viral DNA
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Which enzyme carried in the tail of phage T4 helps it penetrate the bacterial cell wall?
Correct answer C. Lysozyme
In the lysogenic cycle, phage DNA that has become part of the bacterial chromosome is called a ____.
Correct answer C. prophage
A phage such as lambda that can either lyse its host or enter lysogeny is known as a ____ phage.
Correct answer B. temperate
A virulent bacteriophage differs from a temperate one in that it ____.
Correct answer B. always destroys its host by the lytic cycle
How is a prophage passed on to new bacterial cells?
Correct answer A. It is replicated with the bacterial chromosome at each cell division
Exposure of lysogenic bacteria to ultraviolet light often causes ____.
Correct answer C. the prophage to excise and start a lytic cycle
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A bacterium carrying a prophage in its chromosome is described as ____.
Correct answer C. lysogenic
HIV is placed in the retrovirus group because it ____.
Correct answer D. copies its RNA genome into DNA using reverse transcriptase
Which enzyme of HIV inserts the viral DNA into the chromosome of the host cell?
Correct answer D. Integrase
The genome of a single HIV particle consists of ____.
Correct answer A. two copies of single-stranded RNA
Which cells of the immune system are the principal target of HIV?
Correct answer A. Helper T lymphocytes carrying CD4
Which HIV envelope glycoprotein binds to the CD4 receptor of a host cell?
Correct answer D. gp120
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Which activity carries no risk of passing on HIV?
Correct answer B. Shaking hands or sharing cups with an infected person
HIV can pass from an infected mother to her baby by which route?
Correct answer B. Across the placenta, at birth or through breast milk
Why do people with advanced AIDS suffer repeated opportunistic infections?
Correct answer A. Their helper T cell count falls so low that immune responses fail
Roughly how many kilocalories of energy are released when the terminal phosphate bond of ATP is broken?
Correct answer B. 7.3
During which process are ATP molecules consumed?
Correct answer B. Glycolysis